Über Emphysembildung und Pneumocephalus internus

Ohne ZusammenfassungHerrn Prof.Güttich zum 60. Geburtstag.     

Serum insulin and plasma glucagon in human pregnancy — On the pathogenesis of gestational diabetes. A review

Summary The possibility that the deterioration of glucose tolerance during pregnancy might be due to a change in the functional condition of the endocrine pancreas has been examined in normal pregnant women and in non-obese gestational diabetics. Three test-situations were applied to elucidate the problem: 1) an overnight fast; 2) a glucose tolerance test (OGTT); and 3) a protein-rich meal. After the overnight fast, hyperinsulinemia and hyperglucagonemia were found in late pregnancy in both groups. However, on a molar basis, basal insulin increased more than basal glucagon and the molar insulin: glucagon ratio was therefore increased. After oral administration of glucose, the insulin response was enhanced in the late stages of pregnancy both in normal women and in those with gestational diabetes while the depression of glucagon below fasting levels was exaggerated and sustained in both groups. In response to a protein-rich meal in normal late pregnancy, the glucagon response was significantly lower than post partum in the same subjects, whereas that of insulin was unchanged. Finally, in both groups the diminished glucose tolerance in pregnancy was not associated with an abnormally elevated proportion of total insulin immunoreactivity represented by the biologically almost inactive proinsulin. Based upon these findings and those reported in the literature, it is concluded that there is no evidence in support of the idea that the diabetogenicity of pregnancy can be explained by changes in the function of the endocrine pancreas in these patients.     

Pharmacology of the urotensin-II receptor antagonist palosuran (ACT-058362; 1-[2-(4-benzyl-4-hydroxy-piperidin-1-yl)-ethyl]-3-(2-methyl-quinolin-4-yl)-urea sulfate salt): first demonstration of a pathophysiological role of the urotensin System

Urotensin-II (U-II) is a cyclic peptide now described as the most potent vasoconstrictor known. U-II binds to a specific G protein-coupled receptor, formerly the orphan receptor GPR14, now renamed urotensin receptor (UT receptor), and present in mammalian species. Palosuran (ACT-058362; 1-[2-(4-benzyl-4-hydroxy-piperidin-1-yl)-ethyl]-3-(2-methyl-quinolin-4-yl)-urea sulfate salt) is a new potent and specific antagonist of the human UT receptor. ACT-058362 antagonizes the specific binding of (125)I-labeled U-II on natural and recombinant cells carrying the human UT receptor with a high affinity in the low nanomolar range and a competitive mode of antagonism, revealed only with prolonged incubation times. ACT-058362 also inhibits U-II-induced calcium mobilization and mitogen-activated protein kinase phosphorylation. The binding inhibitory potency of ACT-058362 is more than 100-fold less on the rat than on the human UT receptor, which is reflected in a pD'(2) value of 5.2 for inhibiting contraction of isolated rat aortic rings induced by U-II. In functional assays of short incubation times, ACT-058362 behaves as an apparent noncompetitive inhibitor. In vivo, intravenous ACT-058362 prevents the no-reflow phenomenon, which follows renal artery clamping in rats, without decreasing blood pressure and prevents the subsequent development of acute renal failure and the histological consequences of ischemia. In conclusion, the in vivo efficacy of the specific UT receptor antagonist ACT-058362 reveals a role of endogenous U-II in renal ischemia. As a selective renal vasodilator, ACT-058362 may be effective in other renal diseases.     

Combination of real-time PCR and sequencing to detect multiple clinically relevant genetic variations in the lactase gene

Background: Lactase persistence is an autosomal dominant trait commonly distributed in Europe as well as some parts of east Africa and the Arabian Peninsula. Using real-time PCR to detect the ?13910C?>?T variant common in the European population is a reliable analysis although other variants in the probe-binding site may cause errors in analysis. The aim of this study was to determine the prevalence of the variants in a Danish cohort examined for lactose intolerance as well as to improve the real-time PCR analysis for detection of the different variants.

Methods: We genotyped 3395 routine samples using real-time PCR for the ?13910C?>?T-variant. All consecutive samples identified as ?13910CC were sequenced using Sanger Sequencing. Using the SDS software we examined various quality value settings to improve on the genetic analysis.

Results: Using real-time PCR resulted in 100% successful genotyping of the ?13910C?>?T variant. By using a quality value of 99% and sequencing the undetermined samples we improved the ability of the assay to identify variants other than ?13910C?>?T. This resulted in a reduction of the diagnostic error rate by a factor of 2.4 while increasing the expenses only 3%.

Conclusions: We conclude that using a quality value of 99% in the SDS software significantly improves the diagnostic efficiency of the real-time PCR assay for detecting variants associated to lactase persistence.     

The Effect of Preoperative Intra-Articular Methylprednisolone on Pain After TKA: A Randomized Double-Blinded Placebo Controlled Trial in Patients With High-Pain Knee Osteoarthritis and Sensitization

In a randomized, double-blind, placebo controlled trial, we investigated the postoperative analgesic effect of a single intra-articular injection of 40?mg methylprednisolone acetate (MP) administered 1 week before total knee arthroplasty (TKA). Forty-eight patients with high pain osteoarthritis (≥5 on a numeric rating scale during walk) and sensitization (pressure pain threshold?<250?kPa), aged 50 to 80 years and scheduled for primary unilateral TKA under spinal anaesthesia were included. The primary outcome was the proportion of patients with moderate/severe pain during a 5-m walk test 24 hours postoperatively. Secondary outcomes included pain at 48 hours, during the first 14 days, sensitization (quantitative sensory testing with pressure pain threshold and wind-up from temporal summation), and inflammatory changes (systemic C-reactive protein, intra-articular interleukin [IL]-6). No difference in the proportion of patients with moderate/severe pain was found between MP/placebo groups at 24 hours (67% and 74%, χ²?=?.2, P?=?.63, odds ratio = .7, 95% confidence interval = .2–2.8) or at 48 hours (57% and 68%, χ²?=?.5, P?=?.46, odds ratio = .6, 95% confidence interval = .2–2.3), and no difference between groups in postoperative sensitization was found (P?>?.4) despite reduced preoperative intra-articular inflammation (IL-6) in the MP group versus placebo (median change in IL-6 = ?70?pg/mL, interquartile range = ?466 to 0 vs. 32?pg/mL, interquartile range = ?26 to 75, P = .029). Alternative central or peripheral analgesic interventions in this high-risk group are required.

THE R?LE OF THE RETICULO-ENDOTHELIAL SYSTEM IN IMMUNITY : VI. THE EFFECT OF ENDOTHELIAL BLOCKADE ON THE STORAGE AND DISTRIBUTION OF NEOARSPHENAMINE

1. Blockade of the reticulo-endothelial system by means of a single injection of India ink caused a marked retention of neoarsphenamine in the blood of guinea pigs during the first twenty minutes of observation after intravenous injection, as contrasted with the rapid disappearance of the drug from the blood of normal controls. 2. Rabbits blocked by a single dose of India ink showed a slower elimination of the drug from the circulation following the first few hours after intravenous injection than corresponding controls. 3. The arsenic content of the liver of mice, which received neoarsphenamine intravenously after a preceding blocking injection with India ink, was appreciably lower than the arsenic content of the normal organ under similar experimental conditions.     

Does tumour necrosis factor‐α inhibitor infliximab induce histological resolution of pulmonary sarcoid granulomas?

Background: Sarcoid granuloma formation involves the orchestration of cytokines and chemokines, which modulate the host's immune response to the antigen stimulus. The release of cytokines enhances expression of the pro‐inflammatory cytokine tumour necrosis factor‐α (TNF), which plays a crucial role in the formation of sarcoid granuloma, being released from T‐lymphocytes and alveolar macrophages. Objective: The aim of this study was to evaluate the effect of infliximab in a case of pulmonary sarcoidosis using a histological approach. Materials and Methods: A 44‐year‐old man with biopsy verified chronic pulmonary sarcoidosis being resistant to treatment with corticosteroids and cell cycle inhibitors. Persisting disease activity was confirmed by declining lung function tests and a positive fluorine‐18‐fluorodeoxyglucose–positron emission tomography scan. The patient was treated with a single course of infliximab 3‐mg/kg body weight; 11 days later, a single lung transplantation was performed. Immunohistological staining with the macrophage marker CD68 was performed on lung tissue and mediastinal lymph node tissue from both the initial diagnostic evaluation (prior to infliximab) as well as from the explanted lung (after infliximab). Results: Biopsy specimens from lung and mediastinal lymph nodes prior to infliximab demonstrated sarcoid granulomas, and staining with CD68 showed dense infiltration by macrophages (epithelioid cells) in the central part of the granulomas. In contrast, biopsies from the explanted lung after infliximab demonstrated acellular sarcoid granulomas with central amorphous masses, and staining with CD68 showed complete absence of macrophages. Conclusions: In this patient, the TNF inhibitor infliximab appeared to induce resolution of sarcoid granulomas starting with disappearance of macrophages probably caused by cell lysis or apoptosis. Please cite this paper as: Milman N, Andersen CB, Baslund B, Loft A and Iversen M. Does tumour necrosis factor‐α inhibitor infliximab induce histological resolution of pulmonary sarcoid granulomas? The Clinical Respiratory Journal 2007; 1:106–113.     

Naphthylphthalamic acid associates with and inhibits PIN auxin transporters

N-1-naphthylphthalamic acid (NPA) is a key inhibitor of directional (polar) transport of the hormone auxin in plants. For decades, it has been a pivotal tool in elucidating the unique polar auxin transport-based processes underlying plant growth and development. Its exact mode of action has long been sought after and is still being debated, with prevailing mechanistic schemes describing only indirect connections between NPA and the main transporters responsible for directional transport, namely PIN auxin exporters. Here we present data supporting a model in which NPA associates with PINs in a more direct manner than hitherto postulated. We show that NPA inhibits PIN activity in a heterologous oocyte system and that expression of NPA-sensitive PINs in plant, yeast, and oocyte membranes leads to specific saturable NPA binding. We thus propose that PINs are a bona fide NPA target. This offers a straightforward molecular basis for NPA inhibition of PIN-dependent auxin transport and a logical parsimonious explanation for the known physiological effects of NPA on plant growth, as well as an alternative hypothesis to interpret past and future results. We also introduce PIN dimerization and describe an effect of NPA on this, suggesting that NPA binding could be exploited to gain insights into structural aspects of PINs related to their transport mechanism.

Many aspects of plant growth are controlled by the hormone auxin. A distinct feature of auxin is that its hormonal action requires it to be actively transported between cells and ultimately throughout the whole plant in a controlled directional or polarized manner, a process known as polar auxin transport (PAT). The ability of plants to perform PAT is ascribed to the auxin export activity of PIN transporters (1). Plasma membrane PINs can be restricted to a specific side of cells (2), and when this polarity is maintained in continuous plant cell files, the combined activity of identically localized PINs results in auxin flowing in that direction (3). This lays the vectorial foundations for PAT to create local auxin gradients and plant-wide PAT streams that are critical for auxin action and normal plant growth (4, 5).Synthetic PAT inhibitors such as N-1-naphthylphthalamic acid (NPA) were initially developed as herbicides and then subsequently exploited by researchers to identify and characterize the unique PAT-based mechanisms that drive plant development (6). Having been used for over six decades, the question as to how NPA actually inhibits PAT has been keenly pursued. Several putative modes of action have been proposed, but the topic remains to date not fully or satisfactorily resolved (6).Early studies established NPA binding with high affinity to membrane-integral components of plant membranes (7–10). With the later discovery of pin1 mutants bearing their distinct bare inflorescences reminiscent of NPA-treated plants (11), followed by identification of the PIN gene family and gradual confirmation that PINs were NPA-sensitive auxin transporters that mediated PAT (1–5), it was apparent that the physiological and genetic evidence overwhelmingly linked NPA to inhibition of PIN activity (6). However, direct molecular association of NPA with PINs has never been reported (6). Instead, a substantial body of data has accumulated suggesting that the NPA target is not PIN itself, but rather other proteins or complexes that either actively coparticipate in PAT or are indirectly involved in control of PAT components (6, 12). Members of the B-family of ABC transporters, such as ABCB1 and ABCB19, showed high-affinity NPA binding and NPA-sensitive auxin export (1, 12–15), thus leading to proposals that they may either physically interact with PINs, or functionally interact such that their nonpolar auxin export activity contributes to PAT and/or to regulation of PINs (12, 16). In these scenarios, PIN/PAT would be rendered vulnerable to the NPA sensitivity of ABCB. However, these schemes are not yet fully resolved, are not fully consistent with key genetic and physiological data (6), and are particularly obfuscated by ABCB1/19 functioning both interactively and independently from PINs (1, 12, 15–20), with ABCB-PIN interaction occurring in an as-yet-unclarified manner (15, 18).A further twist in assigning ABCBs as the main NPA target is their regulation by their chaperone TWD1/FKBP42 (14, 16), with TWD1 itself also being an NPA-binding protein (14, 17). NPA interferes with this regulation and affects TWD1-ABCB interaction, but curiously NPA cannot bind stably to the ABCB-TWD1 complex (14, 17). As TWD1 has also been implicated in NPA-sensitive actin-based PIN trafficking (17), this has led to a model proposing that TWD1 could mediate the NPA sensitivities of both ABCB and PINs, thus presenting TWD1 as a modulator of PAT (17, 21). In an analogous scheme in some plant species, CYPA immunophilins such as tomato DGT, which are functionally similar to TWD1/FKBP42, are suggested to replace TWD1 in modulating auxin transporters and transducing NPA effects to PINs (12, 21).Similar to TWD1, BIG/TIR3 has also been associated with NPA and PIN trafficking (22). Given the undisputed role of trafficking in controlling PIN polarity (5), these reported effects warrant attention, although they are inconsistent with other reports that NPA perturbs neither vesicular trafficking nor actin dynamics in conditions where auxin transport is inhibited (23, 24). Together with trafficking, phosphorylation is another key modulator of PIN polarity as well as activity (5), so it is not surprising to find hypotheses suggesting that NPA could interfere with critical phosphorylation events (6), particularly as PID, a kinase crucial for PIN trafficking and activation, has also been connected to ABCB function and TWD1/ABCB/NPA interactions (25). Others propose that NPA may mimic natural compounds in their capacity as endogenous regulators of PAT, with plant flavonoids being suspected candidates (6, 26). Since flavonoids can compete with or inhibit ATP-binding in mammalian kinases and ABC transporters (27, 28), and as flavonoids can bind to and inhibit PID (25), a phosphorylation-based NPA mode of action would overlap with this hypothesis and poses the question whether NPA acts similarly as an ATP mimic.With these many potential NPA-affected pathways, there is a need to distinguish between low- and high-affinity NPA targets and possible secondary effects due to prolonged PAT inhibition. Current consensus is that low concentrations of NPA (<10 µM) cause direct inhibition of auxin transporters in PAT (21) and the consequent physiological effects seen in planta (IC₅₀ 0.1 to 10 µM) (7, 9, 19, 23, 29). This is associated with high-affinity binding to membranes (K_d 0.01 to 0.1 µM) (7, 8) and the inhibition of PIN/ABCB activity in short-term auxin transport assays (1, 14, 18, 20, 23). In contrast, NPA is thought to affect trafficking (21, 30) and other non-PAT processes (31) when used at higher doses (50 to 200 µM NPA), presumably via binding to its lower-affinity targets, although excessive NPA exposure may also have fast-acting toxic side effects (23). As the in vitro affinity of TWD1 for NPA is surprisingly low (K_d ∼100 µM) (17), the TWD1-mediated NPA effects on PIN/PAT are thought to be of the low-affinity type and linked to trafficking perturbations (17, 21). However, as NPA is always externally applied to plants or cells, it is not clear how or where the drug distributes or accumulates, and thus there may be discrepancies between actual and reported/apparent effective concentrations, as might be the case for TWD1 (17). Finally, NPA also binds with low affinity to inhibit APM1, an aminopeptidase implicated in auxin-related plant growth, but as with trafficking effects, this low-affinity NPA interaction is not connected to direct regulation of PAT (31).Thus, the available data proffer various indirect mechanisms that could lead to NPA inhibition of PIN-mediated PAT, but the proposed schemes have complicating aspects and struggle at times to satisfactorily explain the prime effects of NPA. Here we propose an alternative simpler scenario involving a more direct link between NPA and PINs that would resolve some of these currently outstanding issues. We present evidence from heterologous transport assays, classical in situ membrane binding, and oligomerization studies which collectively suggest that NPA can interact directly in a high-affinity manner with PINs, leading to conformational or structural effects and inhibition of auxin export activity.